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Publication numberUS5374482 A
Publication typeGrant
Application numberUS 07/984,656
Publication dateDec 20, 1994
Filing dateDec 2, 1992
Priority dateDec 2, 1992
Fee statusPaid
Also published asDE69313796D1, DE69313796T2, EP0602403A1, EP0602403B1
Publication number07984656, 984656, US 5374482 A, US 5374482A, US-A-5374482, US5374482 A, US5374482A
InventorsYehuda Ozari, Lalit Kochar, Vance Hall, Ramesh Lhila
Original AssigneeTti
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Masking tape
US 5374482 A
Abstract
A hand-tearable masking tape comprising a tearable backing and an adherable face which permits the tape to be readily removable from a surface to which the tape is applied, the backing comprising a plastic film containing sufficient filler to bring the Elmendorf tear strength of the film to between about 150 and 300 gms.
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Claims(3)
What is claimed is:
1. In a hand-tearable masking tape comprising a tearable backing and an adherable face which permits the tape to be readily removable from a surface to which the tape is applied, the improvement which comprises employing as the backing a polyethylene film containing sufficient diatomaceous earth as filler to bring the Elmendorf tear strength of the film to between about 150 to 300 gm, the film being translucent and having a tensile strength of at least about 100 kg/cm2.
2. A tape according to claim 1, wherein the diatomaceous earth is present in about 25 to 60% the weight of the polyethylene in the backing.
3. In the painting of a selected area of a surface while protecting another area of said surface from receiving paint by covering such other area with a masking tape, the improvement which comprises employing as said masking tape a tape according to claim 1.
Description

The invention relates to a novel masking tape which is easier and less expensive to produce than conventional masking tapes and which possesses certain advantages thereover.

BACKGROUND OF THE INVENTION

Masking tapes are used in painting, lacquering and the like, to protect an area from being treated, i.e. to establish a clear line of demarcation between two areas. For example, in repainting a portion of an automobile, a masking tape would be used to protect an area not to be repainted.

Masking tapes have a backing and an adhesive face. The adhesive face is of limited adhesion so that the tape can readily be removed from the surface to be protected after the operation is complete. The backing is generally paper, usually slightly creped to provide some stretch as might be needed in establishing a curved line of protection.

The backing is usually hand-tearable since the tape is sold in rolls and the user finds it easier simply to tear the tape off the roll cross-wise to the needed length.

For the desired tearability and/or adhesion it has been found necessary first to saturate the paper backing, e.g. with a styrene-butadiene copolymer, then to dry and apply the adhesive layer. The saturation serves to protect against mildew and possible water damage, to prevent paints from penetrating through the porous paper and prevents tape delamination.

The tape is made in wide width and rolled up, being cut into narrow widths, as desired, either before or after rolling up, possibly with additional steps of re-rolling.

OBJECT OF THE INVENTION

While such tapes are reasonable in price and perform adequately, it is an object of the invention to produce less expensively a masking tape which will perform even better.

BRIEF DESCRIPTION OF THE INVENTION

This object is realized in accordance with the invention pursuant to which there is provided a masking tape wherein the conventional impregnated paper backing is replaced by a plastic film which contains sufficient filler to bring the Elmendorf tear strength to from about 150 to 300 gm, i.e. to render it hand tearable.

On the other hand, the tape should still have a tensile strength of at least about 1400 psi (100 Kg/cm2) to permit it to be wound during making and pulled by the user without unintended tearing.

DETAILED DESCRIPTION OF THE INVENTION

Advantageously the plastic film can be formed of any inexpensive polymer such as polyolefin, polyvinyl chloride, polyester, nylon, cellulose acetate, and the like. However for cost and performance polyolefins, especially polyethylene and polypropylene, more particularly low density polyethylene, have proven especially satisfactory.

Even if not perfectly transparent when filled and coated on one face with the adhesive, the resulting films are translucent so the user can see what lies below the applied tape, not possible with present tapes. Moreover such transluscency eliminates gloss and also permits easy writing and printing on the tape.

Whereas when one adds a filler to a film-former the object is usually to minimize strength loss of the resulting film, in the present invention the filler intentionally must substantially reduce the film strength since it usually will not be capable of transverse tearing by hand.

The precise amount of filler needed for this purpose will therefore depend upon the composition of the film, its thickness, other materials present such as plasticizer, and the like.

For polyethylene films of about 0.05 to 0.15 mm in thickness, about 25 to 60% and preferably about 40 to 50% by weight of filler, based on polyethylene, has proven adequate. Suitable fillers comprise inorganics such as calcium carbonate, calcium sulphate, magnesium salts, kaolin, sand, and the like, but organics such as sawdust, starch, cornmeal, ground plastic waste, and the like, can also be used. Its particle size can vary widely, about 0.5 to 10 and particularly about 1 to 4 microns being preferred.

Some fillers, such as diatomaceous earth, perform exceptionally well, much better for example than barytes.

There may also be included other agents for coloring or other properties and/or the fillers themselves may be colored.

The film-forming polymer usually in the conventional form of chips is compounded with the filler and extruded into film in conventional manner. To the film there is then applied the adhesive face, of conventional composition and in conventional manner.

Such adhesives can be any now employed, e.g. water or solvent based acrylic adhesive, natural rubber or synthetic rubber--resin based adhesives, applied from water, solvent or a hot melt medium.

The adhesive is generally applied in from about 15 to 65 and preferably about 15 to 30 grams/m2 and the tape is thereafter converted to rolls of predetermined lengths and widths, possibly with intermediate rewindings and cuttings in width and length.

Even without pretreatment the novel films and tapes resist mildew and are essentially water-proof. Also they do not delaminate and paints will not penetrate.

The invention will be further described with reference to the following illustrative example where all parts are by weight unless otherwise expressed.

EXAMPLE

Low density polyethylene pellets of about 4 micron diameter are mixed and blended with 50% their weight of diatamaceous earth filler powder of about 3.5 micron diameter, and the blend is extruded into a film of 50 microns in thickness and 1.5 meters in width.

To one face of the film there is applied a water-based acrylic latex adhesive, Rhoplex 83D, in a weight of 23 grams per square meter.

The film is cooled to set the adhesive and then rolled up. Thereafter it is cut into lengths of 60 meters and widths of 25 mm.

It will be appreciated that the instant specification and claims are set forth by way of illustration and not limitation, and that various modifications and changes may be made without departing from the spirit and scope of the present invention.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3396837 *Mar 16, 1964Aug 13, 1968Minnesota Mining & MfgPressure-sensitive adhesive masking tape having polypropylene film backing
US3870593 *Apr 29, 1974Mar 11, 1975Minnesota Mining & MfgStretch-oriented porous films and preparation and use thereof
US3993826 *Jan 14, 1975Nov 23, 1976Adhesive Tapes LimitedPolyolefin, thermoplastic elastomer
US4237889 *Sep 13, 1978Dec 9, 1980Minnesota Mining And Manufacturing CompanyDiaper closure utilizing pressure-sensitive adhesive tape having textured foil backing
US4751121 *May 28, 1986Jun 14, 1988Huels Troisdorf AktiengesellschaftMulti-ply self-adhesive and deep-drawable protective sheet, especially for automotive vehicles
US4781957 *Jul 27, 1987Nov 1, 1988Minnesota Mining And Manufacturing CompanyClosely spaced ridges and grooves at right angles to edges; polypropylene film
US4898762 *Jul 1, 1988Feb 6, 1990Minnesota Mining And Manufacturing CompanyEasy tear sterilization indicator tape
US4917944 *Sep 30, 1987Apr 17, 1990Huels Troisdorf AktiengesellschaftMulti-ply weatherable plasticizer-free sheet
US5096761 *Jul 25, 1990Mar 17, 1992W. R. Grace & Co.-Conn.Antistatically conductive masking film for electrostatic spray painting
US5162150 *Aug 20, 1991Nov 10, 1992Milliken Research CorporationPlastic film; non-woven open mesh scrim fabric laminated to film; pressure sensitive adhesive connected to fabric and film; fabric of longitudinal warp yarns, perpendicular glass fiber continuous filament weft yarns connected to warp yarns
US5190816 *Feb 24, 1992Mar 2, 1993Arizona Chemical CompanyPolyolefin, amphiphile
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US5958580 *Mar 6, 1997Sep 28, 1999Nitto Denko CorporationA substrate comprising a resin of a polypropylene hard segment and an polymerized olefin soft segment; adhesive layer; polymer alloys; softness; applied to curved areas, automobile, motorcycle parts; nontoxic incineration products
US5998018 *Apr 3, 1997Dec 7, 1999Sony Chemicals Corp.Coat masking tape base material, and coat masking tape
US6451425Jun 16, 1999Sep 17, 20023M Innovative Properties CompanyAdhesive tape backing
US6965474Feb 12, 2003Nov 15, 20053M Innovative Properties CompanyPolymeric optical film
US7099083Jan 29, 2004Aug 29, 20063M Innovative Properties CompanyPolymeric optical film
US7110072Jan 29, 2004Sep 19, 20063M Innovative Properties CompanyCompensators for liquid crystal displays
US7132065Feb 12, 2003Nov 7, 20063M Innovative Properties CompanyProcess for manufacturing polymeric optical film
US7405784Feb 12, 2003Jul 29, 20083M Innovative Properties CompanyCompensators for liquid crystal displays with biaxially stretched single film with crystallization modifier
US20130052427 *Jul 6, 2012Feb 28, 2013Cerium Group LimitedComposite protective sheet material
Classifications
U.S. Classification428/343, 428/323, 428/355.00R
International ClassificationC09J7/02
Cooperative ClassificationC09J7/0264
European ClassificationC09J7/02K9B
Legal Events
DateCodeEventDescription
May 30, 2006FPAYFee payment
Year of fee payment: 12
Jun 10, 2002FPAYFee payment
Year of fee payment: 8
May 1, 1998FPAYFee payment
Year of fee payment: 4
Jul 25, 1995CCCertificate of correction
Dec 2, 1992ASAssignment
Owner name: TTI, NEW YORK
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:OZARI, YEHUDA;KOCHAR, LALIT;HALL, VANCE;AND OTHERS;REEL/FRAME:006340/0894
Effective date: 19921013